Hockey pucks are rubber disks having a thickness of about one inch, a diameter of about three inches, and weighing about six ounces. Various rubber compositions for hockey pucks have been devised over the years with most, if not all, of these compositions including natural and synthetic rubber at a ratio of about 1 to 9 as their basic ingredients.
Desirably, hockey pucks should exhibit the quality of being "dead" objects on the ice. That is, the pucks should have little or no bounce to them. Such bounciness is determined by the coefficient of restitution exhibited by the puck. The lower the coefficient of restitution, the less bounce the puck will have. Thus, the puck, upon hitting an object such as the ice rink wall, will drop to the ice rather than rebounding quickly from the wall.
Heretofore, hockey pucks have had to be frozen prior to a game in order to lower the coefficient of restitution. However, during the game, the pucks warm up and therefore, the coefficient of restitution increases, resulting in the same adverse properties which were initially eliminated with the freezing of the puck. Desirably, the puck should have the same consistent rebound and bounce no matter what the temperature of the rubber puck is.
Notwithstanding the disadvantages associated with freezing them, the pucks of the prior art have also been known to chip or peel during play. As the pucks are used over and over, they have a tendency to chip or be cut during use. Thus, it would be desirable to produce a puck which exhibits superior cut strength and increases chip and abrasion resistance as compared to other pucks of the prior art. More importantly, it is desirable to produce such a puck which would display little or no change in these properties no matter what the temperature and other conditions are.
Difficulty is often experienced by spectators of hockey games in seeking to track the puck. The problem is accentuated when the game is viewed through electronic media such as television. Accordingly, there is a need to make hockey pucks of a more visible nature. It is noted from an article in the Oct. 8, 1990 edition of Sports Illustrated (Vol. 73, Issue 15) that various colored pucks have been attempted. Many have been painted, but the paint came off under game conditions. Plastic coatings were used, but were too costly. Dyes were used, but faded or caused the puck to warp. Others became mushy and bounced unpredictably upon extensive use. However, the rubber composition of the puck is believed to be at least partially to blame for the problems associated with colored pucks. Therefore, a rubber composition for a puck which is not affected by the incorporation of coloring pigments or dyes and/or permits adhesion of visual materials and coatings to the surface thereof is believed to be highly desirable.